"Data suggest that receptor complex assembly from Chrna4 and Chrnb2 on neuronal cell surface is up-regulated by nicotine; combined effects of increased assembly stoichiometry and preferential trafficking likely drive up-regulation of this receptor complex on neuronal cell surface upon nicotine exposure. (Chrna4 = a4 nicotinic receptor; Chrnb2 = b2 nicotinic receptor)"xsd:string